8.5 Identity PSK Feature Deployment Guide

Product or Feature Overview 2

IPSK solution 3

Configurations Steps for IPSK in 8.5 release 3

Controller Configuration Steps 6

WLC Local Policies Combined with IPSK 10

Introduction to Profiling and Policy Engine on the WLC 12

Scope and Objectives 12

Profiling and Policy Configuration 13

Mapping Policy on WLAN 18

End User Device Setup 21

Conclusion 22

IPSK Configuration through CLI commands 23

Revised: September 14, 2017,

Product or Feature OverviewWith the advent of internet of things, the number of devices that connect to the internet is increased multifold. Not all of thesedevices support 802.1x supplicant and need an alternate mechanism to connect to the internet. One of the security mechanisms,WPA-PSK could be considered as an alternative. With the current configuration, the pre-shared-key is the same for all clients thatconnect to the sameWLAN. In certain deployments such as Educational Institutions, this results in the key being shared to unauthorizedusers resulting in security breach. Therefore, above mentioned and other requirements lead to the need for provisioning uniquepre-shared keys for different clients on a large scale.

• Identity PSKs are unique pre-shared keys created for individuals or groups of users on the same SSID.

• No complex configuration required for clients. The same simplicity of PSK, making it ideal for IoT, BYOD, and guestdeployments.

• Supported on most devices, where 802.1X may not, enabling stronger security for IoT.

• Easily revoke access, for a single device or individual, without affecting everyone else.

• Thousands of keys can easily be managed and distributed via the AAA server.

As depicted in the above diagram, in the Traditional PSK, for all the clients that connect to a particular SSID, the key would remainsame leading to security issues. With Identity PSK, every client connecting to the same SSID can have potentially a different key.

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IPSK solutionDuring client authentication, the AAA server would authorize the client mac address and send the passphrase (if configured) as partof the Cisco-AVPair list. TheWLCwould receive this as part of the radius response and would process this further for the computationof PSK.

When the client sends association request to the SSID broadcasted by the access point, the Wireless LAN Controller forms theRADIUS request packet with the particular mac address of the client and relays to the RADIUS server.

The RADIUS server performs the authentication and checks whether the client is allowed or not and sends either ACCESS-ACCEPTor ACCESS-REJECT as response to the WLC.

To support Identity PSK, in addition to sending the authentication response, the authentication server would also provide the AV Pairpassphrase for this specific client. This is used further for the computation of PSK.

The RADIUS server could also provide additional parameters such as username, VLAN, QoS, etc in the response, that is specific tothis client. For multiple devices that is owned by a single user, the passphrase could remain the same.

Configurations Steps for IPSK in 8.5 releaseIPSK can be configured on any AAA serer that supports Cisco av-pair. In this deployment guide we focus on the configuration onthe Cisco Identity Service Engine. ISE 2.2 Configuration Steps

Procedure

Step 1 Add wireless controller under test on ISE as shown below with a secret password configured in "Radius AuthenticationSetting" and then Submit the configuration.

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Step 2 Create an Authorization Profile and verify it Under Policy>Results>Authorization> Authorization Profiles IPSK-Deviceas shown in example below.

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Step 3 Create Authorization profile With Access Type Access_Accept with cisco-av-pair(s) with psk-mode and psk password asshown in the example below is configured.

Step 4 Under Policy> Authorization Configure Rule for every Device or User MAC address to be used with IPSK as shown inexample below. Use as many Mac address entries as you wish.

Rule is linked to the Profile created in step3.

Note

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Make sure Mac address of the device configured properly. We have configured Apple MacBook laptop Macaddress for this Exercise.

Note

Step 5 Verify every step performed above and make sure all configuration are applied and saved.

Controller Configuration Steps

Procedure

Step 1 Create WLAN on your controller as in the shown example Pod1-IPSK.

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Step 2 Configure WLAN with Security WPA2/PSK and enableMAC filtering. In the example below the PSK key used isPSK=12345678.

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Step 3 ConfigureWLANwith SecurityWPA2/PSK and configure PSK. In the example below the PSK key used isPSK=12345678.

Step 4 Configure on the WLC the Authentication Server with ISE IP address and apply it to WLAN Pod1-IPSK created in thesteps above. In our example, ISE IP address is 10.91.104.106.

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Step 5 Lastly, under WLAN advanced settings enable AAA Override.

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WLC Local Policies Combined with IPSKJust like AVC, mDNS or Open DNS profile can be mapped to a local policy for a client with a particular device type.IPSK also canbe combined with Local policies on the controller and mapped to a specific WLAN. When configuring the AV-pair=PSK-mode andPSK-password on the AAA server such as ISE, admin can easily add another AV-pair=role for example for a teacher or a studentgroup and then configure a Local policy to that specific Role.Each local policy can be configured with a different profile name, ACL,Role, Device Type and even Active Hours based on the AAA override to restrict/permit the policy from being able to use/deny theservices not allowed by the profile on the same WLAN.

When combining IPSK and Local Policies on the sameWLAN the use cases can be unlimited and open to many different deploymentscenarios.

For example on campus admin can configure a use case where students have to login with IPSK and then apply local policy that onlythose students belonging to the group Students can access specific applications at certain bandwidth on specific device and duringspecific time. There practically unlimited set of capabilities and tweaks available when combining the two.

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Introduction to Profiling and Policy Engine on the WLCCisco currently offers a rich set of features which provide device identification,on boarding,posture,and policy,through ISE. Thisnew feature on the WLC does the profiling of devices based on protocols such as HTTP, DHCP, and so on to identify the end deviceson the network.The user can configure the device-based policies and enforce per user or per device policy on the network.The WLCwill also display statistics based on per user or per device end points and policies applicable per device.

With BYOD (Bring your own device), this feature has an impact on understanding the different devices on the network. With this,BYOD can be implemented on a small scale within the WLC itself.

Scope and ObjectivesIn this section, we will be configuring and implementing Profiling and Policy on a Cisco WLC running AireOS8.5 code.

The profiling and policy enforcement will be configured as two separate components. The configuration on theWLC is based ondefined parameters specific to clients joining the network with IPSK security as configured in the previous sections. The policyattributes which are of interest are:

1 Role–Role defines the user type or the user group the user belongs to.

2 PSK-mode ASCII

PSK-password–match of the specific PSK password with the device MAC address

For example: Student or Employee

3 Device–Device defines the type of device.For example: Windows machine, Smart phone, Apple device such as iPad, iPhone and so on.

4 Time of day–Allows configuration to be defined at what time of the day end-points are allowed on the network.

The above parameters are configurable as policy match attributes. Once the WLC has a match corresponding to the above parametersper end-point,the policy enforcement comes into picture. Policy enforcement will be based on session attributes such as:

• VLAN

• ACL

• Session Timeout

• QoS

• Sleeping Client

• Flexconnect ACL

• AVC profile

• mDNS profile

• Open DNS profile

• Security Group Tag

The user can configure these policies and enforce end-points with specified policies.The wireless clients will be profiled based onthe MAC address, MAC OUI, DHCP, and HTTP user agent (valid Internet required for successful HTTP profiling).The WLC usesthese attributes and predefined classification profiles to identify the device.

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Profiling and Policy Configuration

Procedure

Step 1 To configure device profiling on a WLAN, go to the specific WLAN on which you want to implement Native profilingand policy and click Advanced. Disable Allow AAA Override if it is enabled. In the DHCP area, check the Requiredcheck box for DHCP Addr. Assignment.

Step 2 After enabling the DHCP required option, scroll down and in the Local Client Profiling area, enable DHCP Profilingand HTTP Profiling if they are not enabled and click Apply.

Creating Policies on the WLAN from the WLC GUI

Step 3 Once Profiling is configured, we can move on to create Local policies and apply them on the WLAN. On the WLC menubar,go to Security > Local Policies,which will take you to the Policy List.

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Step 4 When in the Local Policy List, click New to create a Policy Name. In this example, teacher-LP is used as a policy name,but you can use any name to define your own policy.

Once policy name is configured,you can create policies to match a Role, EAP Type, and DeviceType. Also,you can definethe required actions related to the Match criteria.

Here, in our setup we use User Role and Device Type to Match Criteria, but you can use any other type if required.

Make sure Match Role string is the same as AAA defined role name. In this example, it is configured as teacher.Note

Step 5 Enter User Role and click Apply. Here the role name "teacher" is used as an example.Step 6 To apply the policy based on a user device, in the Device List area, from the Device Type drop-down list, choose the

device type on which you want to enforce the policy and then click Add.Here, we used Apple-iPad as a device type forMatch Criteria. You can add Apple-iPhone and other Apple devices aswell from the Device Type drop-down list.

If you do not want to match any device type then do not configure theDevice Type option.Note

Step 7 To apply the appropriate action, choose from the parameters under the Action area to enforce the policy. Select the AVCprofile that should be defined in the last section.

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For additional details on configuring Local Policy please see the link http://www.cisco.com/c/en/us/td/docs/wireless/controller/8-3/config-guide/b_cg83/b_cg83_chapter_01110.html

Note

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Step 8 User can create more than one Local policy and apply it for student as “student-LP”.Ensure that theMatch Role String is the same as the defined role name on the AAA/Radius Server.Note

Step 9 Create a default local policy for any other device.If no other ACL is applied in the Local policy,then any other device,other than Apple-iPad, will beable to access theapplications because the final filter function of all policies is Allow all.

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In order to block all applications on all devices except Apple-iPad, create a deny all ACL and apply it on the Local Policyand then apply that policy on the WLAN as the last resort.See the configuration examples in the screenshots below.

Create an ACL to deny all IPv4 flow.

Create a Local Policy Block-all and apply thedeny allACL to it, do not choose any devices roles or profiles.

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Mapping Policy on WLAN

Procedure

Step 1 Go toWLANs from the WLC menu bar and click theWLAN ID on which you want the policy to be implemented. Fromthe WLAN edit menu, click the Policy-Mapping tab.Set the Priority index to any value from 1-16. From the Local Policy drop-down list, choose the policy which you havealready created. To apply the policy on the WLAN, click Add. The policy will be added.

Step 2 Add the appropriate policies to Policy-Mapping under WLAN.

Step 3 In the Advanced tab, disable Allow AAA Override if it is enabled as was configured also for IPSK.

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Step 4 Check if the AAA role is configured properly, that is, role name on the AAA server should match the role string definedin the local policy. The example below is from the Cisco ISE server configured with cisco-av-pair role=teacher. Sameconfigure for role=students.

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End User Device Setup

Procedure

Step 1 On the End User device withMAC address configured on ISE connect to theWLAN Pod1-IPSK and enter IPSK passwordabc12345 for that device or as it was configured on ISE.----- Connection successful

Step 2 Connect to the same WLAN with PSK 12345678.---- connection will be un-successful

Step 3 Connect to the same WLAN with device MAC address not configured on ISE with PSK 12345678.---– connection successful

Step 4 To verify if the policy is applied from the WLCGUI, go toMonitor > Clients, and then click the Client MAC address.

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Conclusion• Controller that has Mac Filtering and AAA overide enabled with ISE configured, will allow IPSK configured devices connectto WLAN with MAC addresses configured on ISE.

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• Devices withMAC addresses configured on ISEwill not be able to connect toWLAN generic PSK but only with IPSK configuredfor that device.

• Devices with no-MAC addreses configured on ISE will be able to connect to WLAN with generic PSK only.

• IPSK is not supported on the Flex Connect locally switched mode. AAA server is required with AV-Pair support.

• IPSK is not supported on the Flex Connect Group.

• IPSK supports FSR and key caching is done fo faster roams to avoid RADIUS connect on every roam.

• To enable validitsy of the IPSK at certain scheduled times - the time schedule/validity can be exploited using radius session-timeoutattribute in radius response.

IPSK Configuration through CLI commandsThe following existing CLIs would be used for this feature:config wlan mac-filtering enable <wlanId>config wlan aaa-override enable <wlanId>config wlan security wpa akm psk enable <wlanId>config wlan security wpa akm psk set-key <ascii/hex> <key> <wlanId>

The existing show command would display the configuration of the WLAN and the client.show wlan <wlanId>show client detail <clientMac>

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